BMX Race Cranks

What distinguishes a BMX Race Crank?

A BMX Race Crank is a pure propulsion machine. It must be extremely stiff to convert the explosive power at the gate into speed without loss. Compared to freestyle cranks, they are significantly lighter, often use aluminum or carbon instead of steel, and usually have an integrated "spider" (4-arm mount) for mounting large chainrings.

How is a race crank constructed?

Crank Arms

Mostly made of hollow-forged aluminum or carbon. They are thicker than road bike cranks but lighter than street BMX cranks.

Spindle (Axle)

The standard in modern racing is 24mm hollow axles (similar to the Shimano Hollowtech II standard) or even 30mm on high-end models. This offers more stiffness than the thinner 19mm axles from freestyle.

Spider

A crucial difference: Race cranks usually have a 4-arm star with a 104mm Bolt Circle Diameter (BCD). This allows for quick gear ratio changes without removing the crank.

What types are there?

2-Piece

The current standard in racing (e.g., CLIQ, Forward). One crank arm is permanently connected to the axle. This saves weight and increases stiffness.

Square Taper

Still found on very small sizes (Mini/Junior). Here, the crank is pressed onto a cartridge bearing.

What materials are used?

Aluminum (6061/7075)

The dominant material. It offers the best balance of weight, stiffness, and price.

Carbon

The absolute high-end class. Carbon cranks are extremely light and stiff but require careful installation with a torque wrench.

CrMo Steel

Almost only used in the entry-level or old-school sector, as it is often too heavy for pure racing purposes.

Which crank length do I need?

The length of the crank arms is the most important lever for your power. A crank that is too long hinders your cadence ("spin"), while a crank that is too short reduces leverage at the start.

How do I install my race crank?

1. Install the appropriate bottom bracket (often Euro BB/BSA with external cups or Pressfit BB86).
2. Slide the axle (with the fixed arm) through the bearing. Use spacers to adjust the chainline.
3. Place the second crank arm onto the splines.
4. Tighten the preload bolt hand-tight until there is no play.
5. Tighten the clamping bolts on the crank arm evenly with an hex key.
6. Don't forget the pedals: Note the right and left threads!

What do the specifications mean?